Scanned light beams are used to produce display images for a wide variety of applications, including such applications as mobile microprojectors, automotive head-up displays, and head-worn displays. The displays are created by using the angular motion of a mirror to deflect a modulated light beam to cover the desired field of view. By moving the mirror about two orthogonal axes, a rectangular field of view can be created, providing the familiar look of a raster display in a compact and portable package.
Controlling the mirror deflection to correctly produce the desired angular motion presents a significant engineering challenge. This is due, in part, to the fact that mirrors are mechanical devices that exhibit vibration modes at various resonant frequencies.